The Ebola virus has been identified as the source of an outbreak of hemorrhagic fever in southern Guinea, the west African nation said on Saturday as the death toll rose to 34.

Experts in Guinea had been unable to identify the highly contagious disease, whose symptoms – diarrhoea, vomiting and bleeding – were first observed six weeks ago. But scientists in the French city of Lyon confirmed it was Ebola, the Guinean health ministry said.

"We got the first results from Lyon yesterday [Friday] who informed us of the presence of the Ebola virus as the cause of this outbreak," said Sakoba Keita, the ministry's chief disease prevention officer.

"Up to today, we have identified 49 cases with 34 deaths in four prefectures."

To date, no treatment or vaccine is available for Ebola, which kills between 25% and 90% of those who fall sick, depending on the strain of the virus, according to the World Health Organisation.